1. Field of the Invention
The present invention generally relates to multiprocessor computer systems and more particularly relates to exclusive access by a processor to shared resources in the multiprocessor computer system.
2. Description of the Related Art
Multiprocessor computer systems combine multiple processors into a single computer system to achieve greater capacity and computational power. In a multiprocessor system, a processor may need exclusive access to shared resources. A typical technique for gaining exclusive access is to use a semaphore or other similar memory location to control access to the shared resource. A processor reads the semaphore to determine if it is available, then writes the semaphore to indicate the processor controls the semaphore if it was available. however, in a multiprocessor system, care must be taken to make this an atomic operation, to prevent one processor from writing to the semaphore after another processor has read the semaphore.